Beta-thymidine is of interest in the synthesis of pharmaceuticals useful, for example, in the treatment of patients suffering from acquired immunodeficiency syndrome (AIDS).
Known processes for synthesizing beta-thymidine, while operable, tend to be tedious, time-consuming, and expensive. For example, a common way of producing beta-thymidine involves a coupling reaction between protected deoxyribose and a protected thymine. Unfortunately, this route results in the formation of mixed alpha- and beta-anomers of the protected thymidine. Note in this connection A. J. Hubbard, et al. Nucleic Acids Research, 1984, 12, 6827 et seq.; U. Nieballa, et al. J. Org Chem. 1974. 39, 3654 et seq.; and H. Vorbruggen, et al. U.S. Pat. No. 3,748,320. Since the alpha-anomer is not useful for the intended purpose, it must be separated from the beta-anomer. In addition, the formation of the alpha-anomer results in loss of raw materials and reduced process efficiency. Inasmuch as deoxyribose is a relatively expensive starting material, its loss due to formation of the alpha-anomer results in economic penalties which are not inconsequential.
A process which would selectively produce the desired beta-anomer would be a welcome contribution to the art. This invention is believed to fulfill this need in an expeditious, efficient and economical manner.